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Theorem pm2.621 397
Description: Theorem *2.621 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm2.621 ((φψ) → ((φ ψ) → ψ))

Proof of Theorem pm2.621
StepHypRef Expression
1 id 19 . 2 ((φψ) → (φψ))
2 idd 21 . 2 ((φψ) → (ψψ))
31, 2jaod 369 1 ((φψ) → ((φ ψ) → ψ))
Colors of variables: wff setvar class
Syntax hints:  wi 4   wo 357
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 177  df-or 359
This theorem is referenced by:  pm2.62  398  pm2.73  818  pm4.72  846  undif4  3607
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